Left ventricular papillary muscles are believe to be the last portions of myocardium to be perfused by arterial blood. We reason that chronic anemia might cause inadequate perfusion of the papillary muscles. To see if this hypothesis might be correct we examined left ventricular papillary muscles in 13 patients with chronic anemia secondary to sickle-cell disease. The patients ranged in age from 13 to 45 years. Histologic study of the papillary muscles show 9 of the 13 patients had foci of fibrosis in them. The lumens of the major coronary arteries in all but 1 patient were wide open. Thus, chronic anemia appear to be the cause of the fibrosis of the left ventricular papillary muscles in these patients.